Wiener, G. (Johns Hopkins Univ. School of Hygiene and Public Health, Baltimore, Md. 21205) and T. Milton. Demographic correlates of low birth weight. Amer. J. Epid., 1970, 97: 260–272.—Data from 100, 277 certificates of live births were analyzed in an attempt to uncover independent correlates of birth weight and gestation time. Without statistical control, each of these variables was shown to be significantly related to race, trimester of obtaining prenatal care, mother's age, parity, socioeconomic status, and legitimacy status. Regression analyses indicated that mother's race and the trimester in which she obtained prenatal care were the most significant correlates of birth weight and gestation time, It was suggested that race and trimester of obtaining prenatal care were not, in themselves, “causes” of low birth weight. Other indices of socioeconomic, cultural, biological, medical, and psychologic factors may be correlated with mother's race and the trimester in which she obtains prenatal care.